The present invention generally relates to machines for forming, filling and sealing plastic bags and, more particularly, to horizontal form, fill and seal machines for zipper bags and to a method for forming, filling and sealing zipper bags.
Plastic bags with reclosable zippers of the type closed by finger pressure are commonly formed on vertical and horizontal form, fill and seal machines. Vertical form, fill and seal machines typically wrap film around a tube. Seals are made in the film to form a bag and product is dropped through the tube into the bag. Overwrap form, fill and seal machines typically wrap film around a product and seal the film to form a bag. Horizontal form, fill and seal machines generally fold film, transverse seal into a three sided package, drop product into the package, and seal the package closed.
Early form, fill and seal machines wrapped film around a product or dropped a product into an envelope and the film was sealed on all sides of the product. Once these bags were opened, they could not be reclosed and other containers were used to store left over product. Many products purchased today are packaged with these early form, fill and seal methods. To meet a need for reclosable bags, zippers that could be closed by finger pressure were developed. New form, fill and seal machines were developed to form and fill these bags.
Recently, reclosable zippers with sliders that open and close the zippers have been developed. To form and fill bags with the slider zippers requires mounting sliders onto zippers, securing the zippers to bag film, forming a bag from the film, and filling the bag with product. It is desirable to perform all of these steps continuously in order to maximize efficiency and minimize the cost of the bags.
The present invention provides a product filled bag that is reclosable by a zipper. The zipper is opened and closed by a slider mounted on the zipper. The bag is made and filled by a form, fill and seal machine that starts by slitting a web of film into a first web portion and a second web portion. The first web portion is folded by a folding board to a position approximately vertical or perpendicular to the second web portion. In this position, the first web portion is accessible for securement of one track of a zipper. A continuous zipper with sliders mounted on it at predetermined intervals is fed to a sealer which seals one track of the zipper to the first web portion. Thereafter, another folding board folds the second web portion adjacent to and parallel with the first web portion. A second track of the zipper is sealed to the second web portion. Side seals are then formed in the web portion and are cut to form individual bags. Product can be filled into the bags before or after the cutting.